Getchar Function in C

This function is a c standard library function found in stdio header file.

Function prototype is as follows:

#include<stdio.h>
int getchar(void);

Return Type :

int , it is an unsigned character value then converted to int which is read from the standard input device that is the keyboard. Return EOF if any errors occurred.

Parameters

No parameters are required to pass. Hence it is void.

//getchar example to read a single character
#include<stdio.h>
int main(int argc, char const *argv[])
{
  int x=getchar();
  putchar(x);
  return 0;
}
getchar in c
//getchar to read a word
#include<stdio.h>
int main(int argc, char const *argv[])
{
  int x;
  
  while ( (x=getchar())!='\n')
  {
  	putchar(x);
  }
  return 0;
}
getchar in c to read a word

Basic Concepts About getchar in c

It is one of the basic input functions of the C programming language.

We have already known that getchar in c function. It is used to read a character from the keyboard.

It is classified as a standard byte input function.

This function reads until it encounters a newline character.

It reads raw input.

This function is specified in ANSI C standards.

Calling getchar in c function is the same as calling getc in c function and passing STDIN as the file pointer.

You can stop this function to take input by pressing Ctrl+D or Ctrl depending on the environment

You may commit a simple mistake by assigning the return value of this function to char data type variable.

What happens if you assign the return value of this function to a char variable?

If a machine allocates 8 bits char variable, there are 256 different values. If the end of the file occurs and it returns EOF. There will be 257 values. This causes a problem.

consider if you are using this function in a while loop, and you are assigning the value to an unsigned char, this function returns EOF, EOF is negative and hence loop never terminates.


People also ask

What is getchar used for?

getchar in c programming language is used for reading a single character from the standard input device. It returns an int value of that character read from char.


What does getchar return in c?

Getchar returns value which is an unsigned character value then converted to int which is read from the standard input device that is the keyboard. Getchar returns EOF if any errors occurred.


What is the difference between getchar and getch?

Now we know about getchar function, let’s have a simple look at getch function also.

getch function is not a standard c library function. It is an MS-DOS function. It is found in conio.h header file.

getchar the function reads a character from the input device and does not displays it on the output console after pressing enter it terminates. getch allows the c program to continue execution without the user pressing the enter key, it does not echo input to the screen.


Why is getchar not working?

Check if you have included the Standard Input Output header file.

If getchar function is after scanf, then you try to read a character from the input device, it reads a new line character. You can use a while loop to ignore all the newline characters as shown below.

c=getchar();
while(c=='\n')
c=getchar();

What is the usage of getchar function in C?

Usually, this function is used to take input of only one character.


What is the problem with the getchar function?

Usually, this function has no problems.

If the programmers don’t know how getchar function works then that causes a problem by using getchar function in the wrong manner.

Programmer uses it in a correct fashion there won’t be any problem at all.

If you want to know about the basic mistakes done by a programmer read the basic concepts about getchar function explained above.


What is the difference between getchar and scanf

The function prototype of scanf in c is int scanf(format_string, vars...);
The function prototype of getchar in c is int getchar(void);

Format and variables as parameters are mandatory for scanf in c.
No parameters are required for getch in c.

Scanf in c reads according to the format specified by the format string.
getchar in c does not requires any format.

Scanf in c returns a number of characters read.
getchar in c returns the read character as int.

Scanf in c reads formatted input.
getchar in c reads a character.

For reference:

scanf in cgetchar
int scanf(format_string, vars...);int getchar(void);
Format and variables as parameters are mandatory.No parameters are required.
Reads according to format.No format is required.
Returns number of characters read.Returns the read character.
It reads formatted input.It reads a character.

What is difference between getchar and putchar

putchar is an output function and getchar is an input function.

putchar writes a single character to the output device. getchar reads a single character from the input device.

putchar in cgetchar in c
It is an output function.It is an input function.
It writes out a single character to output console.It reads a sigle character from input device.